Engineering Commons^™

Modeling Thermosyphon And Heat Pipe Performance For Mold Cooling Applications, Dwaipayan Sarkar

Electronic Thesis and Dissertation Repository

Thermosyphons are enhanced heat transfer devices that can continuously transfer very large amounts of heat rapidly over long distances with small temperature differences. The high heat transfer rate is achieved through simultaneous boiling and condensation of the working fluid and the continuous heat transfer is achieved through recirculation of the working fluid in its liquid and vapor phase. A potentially important application of the thermosyphons has been towards reducing the cycle times of the mold cooling processes which would provide economic incentives to the automotive industry.

Different operational and geometrical parameters such as the input heating power, fill ratio (FR), …

Investigation Of Thermofluid Processes In A Pcm Based Thermal Storage Module, Luca M. Crnjac

Electronic Thesis and Dissertation Repository

Latent heat thermal energy storage systems can capture and store solar thermal energy, enhancing the reliability of solar energy by facilitating a continuous and consistent energy supply. However, phase change materials used in these systems suffer from low thermal conductivities making it difficult to achieve suitable charging and discharging rates. The present research investigated this issue using computational and experimental approaches to improve the design of a thermal storage module through heat transfer enhancement. Various heat transfer enhancements including a finned honeycomb structure, and metal wool were incorporated into a thermal storage module to analyze their effect on charging and …

An Investigation Into Computational Modelling Of Melting And Solidification Of Phase Change Materials, Maryam Hemmat

Electronic Thesis and Dissertation Repository

This thesis evaluates the effectiveness of the enthalpy-porosity approach in simulating melting and solidification of phase change materials within latent heat thermal energy storage systems. It systematically investigates the sensitivity of the computational model to four adjustable parameters: mushy zone coefficient, thermal expansion coefficient, solidus/liquidus temperatures, and latent heat. The study includes individual and combined analyses of these factors in simulations of the melting process by comparing outcomes with extensive experimental data, resulting in a calibrated melting model. The calibrated model is validated across various heating conditions in the cylindrical cavity, and then in a rectangular cavity, confirming its reliability …

Development Of A Computationally Efficient Method For Modelling Thermal Energy Storage In Packed Beds Of Spherically Encapsulated Phase Change Material, Colin Jaffray

Electronic Thesis and Dissertation Repository

A novel computationally efficient method for modelling melting and solidification processes in packed beds of PCM encapsulated spheres is introduced. The proposed method involves the full discretization of only one centrally located sphere to fully simulate the phase change process, while treating all other spheres in the packed bed as voids with boundary conditions derived from the simulated sphere. At each time step, the computed heat transfer parameters on the exterior surface of the simulated sphere undergoing the phase change process are extracted, and imposed as boundary conditions on surrounding spheres. The proposed method results in a significant reduction in …

Diffusion-Dependent Electrodes For All-Solid-State Lithium-Ion Batteries, Peiman Mardani

Electronic Thesis and Dissertation Repository

Electrode design, which is closely related to electronic and ionic transport, has a significant impact on all-solid-state batteries' performance. Typically, a combination of the active material and solid electrolyte serves as the electrode for all-solid-state batteries. An effective scaling technique to spatially organize the two components is essential for high-performance all-solid-state batteries. Here, an electrode design for all-solid-state batteries is given with a higher energy density than the typical composite-type electrode. The first section of the thesis presents a simple electrode design that primarily consists of blended active materials of graphite and phosphorus to meet the demands of all-solid-state batteries …

Numerical Investigation Of Flow And Thermal Behavior In Channels With Pcm-Filled Thermal Energy Storage Columns For Potential Application In Photobioreactors, Sameed Akber

Electronic Thesis and Dissertation Repository

Microalgae has been identified as a potential source in the production of biofuel. Photobioreactors, which are used for microalgae production, normally experience temperature variations over the diurnal cycle due to changes in ambient conditions. The thermal regulation of photobioreactors to minimize temperature variations will result in a higher yield of microalgae, which are sensitive to such variations. The present research is aimed to investigate a novel approach to thermally regulate photobioreactors using phase change materials (PCM) where the latent heat of the material is exploited as the energy storage. The present research uses a numerical approach to study the flow …

Comparison Of Layered Nickel Cobalt Manganese Oxide Cathodes With Different Compositions And Morphologies In Lithium-Ion Batteries, Fanny Poon

Electronic Thesis and Dissertation Repository

The revolutionary rechargeable lithium-ion battery paves the way for environmentally-friendly applications such as electric vehicles. Nevertheless, further improvements are required to match or exceed the performance of conventional internal combustion engine vehicles, such as higher energy density, faster charging speed, longer lifetime, better safety and lower cost. Lithium layered nickel cobalt manganese oxides (NCM) are a popular choice of cathode material, but they still suffer from problems such as cation mixing, volume changes, microcracking, surface side reactions, high temperature performance issues and structural reconstruction. This thesis compares various NCM materials to figure out what guidelines should be followed to improve …

3d Printing Technology Applied In Lithium Metal Batteries: From Liquid To Solid., Xuejie Gao

Electronic Thesis and Dissertation Repository

Li-metal batteries are strongly considered to be one of the most promising candidates for high energy density energy storage devices in our modern society. However, the state-of-the-art Limetal batteries are still limited by several challenges including 1) low energy/power density; 2) Li dendrite growth; 3) low coulombic efficiency, and 4) safety concerns within the liquid electrolyte. This thesis mainly focuses on addressing these challenges by using a 3D printing technique to realize high energy/power density Li-metal batteries.

A self-standing high areal energy density cathode for Li-S battery was developed by the 3D printing method in the first part. The optimized …

Development Of Advanced Solid-State Electrolytes And Interfaces For High-Performance Sulfide-Based All-Solid-State Lithium Batteries, Feipeng Zhao

Electronic Thesis and Dissertation Repository

All-solid-state lithium batteries (ASSLBs) have become increasingly attractive due to the demand of high-energy-density and high-safety lithium-ion batteries for electric vehicles (EVs). As the core component of ASSLBs, solid-state electrolytes (SSEs) are regarded as essential to determine the electrochemical performance of ASSLBs. The inorganic SSEs is one of the most important categories in all developed SSEs, representing the advance of superionic lithium conductors as well as the cornerstone to construct flexible polymer/inorganic composite SSEs. The sulfide-based inorganic SSE is one of the most promising SSEs that is receiving a lot of attentions, because only sulfide SSEs can show ultrahigh ionic …

Geometry Optimization Of Building-Integrated Photovoltaic Sunshade, Seyedsoroush Sadatifar

Electronic Thesis and Dissertation Repository

Building-integrated photovoltaic (BIPV) systems are one of the growing applications of PV technology. These approaches allow PV panels to perform additional functions for the building, such as regulating interior lighting and incoming heat. In this work, we explore a design framework for optimizing the configuration of BIPV shading devices to optimize a combination of power generation, daylighting conditions within the building, and heating and cooling loads.

We develop a generalizable computational model and apply it to a case study for the Cornerstone Architecture Building in London, Ontario. We optimize the configuration of static and dynamic BIPV shading devices in both …

Analytical And Computational Modelling Of The Ranque-Hilsch Vortex Tube, Nolan J. Dyck

Electronic Thesis and Dissertation Repository

The Ranque-Hilsch vortex tube (RHVT) is a simple mechanical device with no moving parts capable of separating a supply of compressed fluid into hot and cold streams through a process called temperature separation. The overall aim is to develop models which can be used to assess the temperature separation mechanisms in the RHVT, leading to a better overall understanding of the underlying physics. The introductory chapter contains a thermodynamic analysis and introduction to the flow physics, alongside three miniature literature reviews and critiques identifying research gaps.

The body of the thesis contains three articles. The first article studies the flow …

Sustainable Smouldering For Waste-To-Energy: Scale, Heat Losses, And Energy Efficiency, Tarek L. Rashwan

Electronic Thesis and Dissertation Repository

Applied smouldering combustion is emerging as a highly energy efficient approach towards waste-to-energy. This thesis aims to better understand this potential by addressing a critical knowledge gap between laboratory scale smouldering research and large-scale applications. Altogether, new understanding in provided on the complex and dynamic interactions between the reaction zone (smouldering front) and the cooling zone (treated inert porous media) by integrating theory, experiments, analytical modelling, and global energy balance calculations. The experiments spanned a range of reactor sizes and smouldering conditions (from weak to robust) with dry (carbon) and wet (sludge) fuels mixed in sand. This work revealed that …

Development Of An Optical Guide For Parabolic Dish Solar Collectors, Zane Charran

Electronic Thesis and Dissertation Repository

With the possibility of a global energy crisis on the horizon, the need for renewable energy processes is more crucial than ever before. Solar energy, specifically solar concentrated collectors can provide a green alternative to fossil fuel consumption, but several factors need to be considered to improve their efficiency and make them viable. The present research is aimed at the development of a novel “Optical Guide” to improve performance of traditional thermal receivers in Parabolic Dish Solar Collectors for use in a domestic solar water heater with PCM latent heat storage integration. Two ray trace programs, SolTrace and Tracer were …

Characterization And Computational Modelling For The Garnet Oxide Solid State Electrolyte Ta-Llzo, Colin A. Versnick

Electronic Thesis and Dissertation Repository

The all-solid-state-battery (ASSB) serves as a promising candidate for next generation lithium ion batteries for significant improvements in battery safety, capacity, and longevity. Of the material candidates researched to replace the conventionally used liquid electrolyte, the garnet oxide Ta-LLZO (Li_6.4La₃Zr_1.4Ta_0.6O₁₂) has received much attention thanks to its high chemical and electrochemical stability, and ionic conductivity which rivals that of liquid electrolytes. While much investigation has taken place regarding the electrochemical performance of Ta-LLZO, much less is known about the micromechanics, including microstructural characterization, stress and strain development, and material failure …

Effect Of The Nonlinear Material Viscosity On The Performance Of Dielectric Elastomer Transducers, Yuanping Li

Electronic Thesis and Dissertation Repository

As a typical type of soft electroactive materials, dielectric elastomers (DEs) are capable of producing large voltage-induced deformation, which makes them desirable materials for a variety of applications in transduction technology, including tunable oscillators, resonators, biomimetics and energy harvesters. The dynamic and energy harvesting performance of such DE-based devices is strongly affected not only by multiple failure modes such as electrical breakdown, electromechanical instability, loss-of-tension and fatigue, but also by their material viscoelasticity. Moreover, as suggested by experiments and theoretical studies, DEs possess nonlinear relaxation processes, which makes modeling of the performance of DE-based devices more challenging.

In this thesis, …

Experimental Investigation Of The Heat Source Orientation On The Transient Flow And Thermal Behaviour Of Phase Change Material During Phase Transition, Steven Jevnikar

Electronic Thesis and Dissertation Repository

The present study reports the characterization of transient flow and transient thermal behavior of phase change material (PCM) during solid-liquid phase change (melting) through experimental investigation. Two specific aspects of the current work, both important in the field of latent heat thermal energy storage, are to investigate the influence of the flow behavior within liquid PCM on the melting and heat transfer processes, and the impact of heat source orientation on the underlying melting and heat transfer processes. A relationship between heat source orientation and the Nusselt number was discussed. The results show that the fluid velocity is critical for …

The Development And Numerical Modelling Of A Representative Elemental Volume For Packed Sand, Ashraf Thabet

Electronic Thesis and Dissertation Repository

The motivation of this thesis is the development of simple microscopic-scale model (representative elemental volume; REV) that can be used to conduct flow and heat transfer simulations from which closure coefficients can be established for the volume-averaged transport equations for porous media (packed bed). The thesis provides a brief introduction to the computational technique adopted for the geometric generation of the REV (YADE), followed by a parametric study undertaken to reveal the minimum number of particles inside the REV that are required to mimic the appropriate physics. Additional analysis was conducted with the goal of determining the influence of deviation …

The Effect Of Mesh-Type Bubble Breakers On Two-Phase Vertical Co-Flow, Alan Kalbfleisch

Electronic Thesis and Dissertation Repository

It is proposed that mesh-type bubble breakers can be used in two-phase gas-liquid vertical cocurrent pipe flow to enhance the heat and mass transfer rates. Two experimental studies were performed to investigate the effect of mesh-type bubble breakers with varying geometries on two-phase flow behaviour. The first used highspeed imaging to measure bubble size and observe the resulting flow regime for two-phase vertical co-flow consisting of air and water. A Froude number correlation that can be used to predict the bubble size generated by mesh-type bubble breakers is proposed. Flow regime maps for two-phase flow in the presence of bubble …

Wind And Thermal Effects On Ground Mounted Photovoltaic (Pv) Panels, Chowdhury Mohammad Jubayer

Electronic Thesis and Dissertation Repository

A combination of Computational Fluid Dynamics (CFD) simulations and wind tunnel experiments are carried out to investigate the effects of wind on the aerodynamic loading and heat transfer of a ground mounted stand-alone photovoltaic (PV) panel with tilt angle of 25^o in open country atmospheric boundary layer. Several azimuthal wind directions are considered: Southern 0^o, Southwest 45^o, Northwest 135^o and Northern 180^o. Three dimensional Reynolds-Averaged Navier-Stokes (RANS) approaches with an unsteady solver using Shear Stress Transport (SST) k-ω turbulence closure are employed for the CFD simulations, whereas Particle Image Velocimetry (PIV) and …

Structural Response Analyses Of Piezoelectric Composites Using Nurbs, Vijairaj Raj

Electronic Thesis and Dissertation Repository

Variational method deduced on the basis of the minimum potential energy is an efficient method to find solutions for complex engineering problems. In structural mechanics, the potential energy comprises strain energy, kinetic energy and the work done by external actions. To obtain these, the displacement are required as a priori. This research is concerned with the development of a numerical method based on variational principles to analyze piezoelectric composite plates and solids. A Non-Uniform Rational B-Spline (NURBS) function is used for describing both the geometry and electromechanical displacement fields. Two dimensional plate models are formulated according to the first order …

Hydrogeological And Thermal Sustainability Of Geothermal Borehole Heat Exchangers, S. Emad Dehkordi

Electronic Thesis and Dissertation Repository

Assessment of the current approach taken by guidelines and design methods of vertical closed loop heat exchangers shows that often groundwater flow is either disregarded or is not methodically incorporated. The state of scientific research in this arena reveals that overlooking the groundwater flow in the design procedure may not always be a correct assumption. The significance of advective heat transport compared to conduction is defined by the groundwater flux or Darcy velocity which heavily depends on the hydraulic conductivity of the ground, followed by the hydraulic gradient which has a relatively limited range. A sensitivity analysis on ground and …

Experimental Investigation Of Wind Effect On Solar Panels, Ayodeji Abiola-Ogedengbe

Electronic Thesis and Dissertation Repository

Photovoltaic Solar Panels for electricity generation are outdoor low-rise structures that are vulnerable to damage by the wind. The existing building codes do not contain information about the impact of the wind on these structures and hence do not provide comprehensive guidelines to mitigate such impact. The present study is a contribution to the ongoing efforts to codify the wind loading on solar panels. In this study, experimental investigations were conducted on the scaled model of a ground-mounted solar panel structure whose surface is geometrically similar to an inclined flat plate and mounted on three-legged support. The panel comprises of …

Parametric Study On A Novel Waste Heat Recovery System, Ghaleb Rustom Abdul Sater

Electronic Thesis and Dissertation Repository

The present thesis is based on an industry-sponsor project involving a novel waste heat-to-electricity conversion system. This proprietary system utilizes thermal energy from a low temperature heat sources to produce torque that drives an electric generator to produce electricity. The system needs to be studied through scientific research to help with optimizing the product development, component design, and overall system performance. The main objectives of this study are to develop simulation tools (numerical model) that will allow to simulate the thermo-fluid processes in various system components and to use this numerical model to study the heat transfer and phase-change processes …

Experimental Investigation Of The Fluid Temperature Field And The Thermal Performance Of Insert Devices In A Flat-Plate Solar Collector, Gurveer Singh Sandhu

Electronic Thesis and Dissertation Repository

An experimental study on the thermal flow behavior inside a flat-plate collector and the impact of insert devices (passive heat transfer enhancement techniques) on the thermal performance of the collector is presented. Temperature fields were obtained for different Reynolds numbers (250-650) and at different inclination angles of the collector. The results show that a stratified flow is developed inside the collector and the warmer fluid restricts itself to the upper portion of the collector only. Various new configurations of the conventional insert devices were tested over a wide range of Reynolds number (200-8000). Comparison of these devices show that in …

Characterization Of Solar Roadways Via Computational And Experimental Investigations, Rajesh Kanna Selvaraju

Electronic Thesis and Dissertation Repository

Efficiency of traditional solar panels is known to be very low and hence necessitates the use of extensive open spaces for producing solar-based electric power. In solar roadways concept, open spaces such as roads, parking lots, bicycle lanes, footpaths are proposed to be utilized. An in-depth quantitative feasibility study for implementing solar roadways in Canada is carried out considering the total available surfaces, solar panel efficiency and effects of fast moving shades. The load carrying capability of commercially available materials for the solar panel top cover is studied in an effort to examine the current as well as near-future implementation …

Development Of Novel Solar Tracking And Heat Extracting Technologies, Hassan Latif Hassan

Electronic Thesis and Dissertation Repository

The global energy and water crises are looming due to the exponential population growth and the shrinking reserves of conventional fossil fuels and fresh water. The present research is aimed at the development of novel components/technologies that would lead to efficient and affordable concentrated solar thermal systems. A novel dual-axis solar tracking system has been developed, built and extensively tested on a field parabolic dish solar collector model. The tracker has two main novel components; active dual axis tracker; and load compensator. The tracker is characterized with simplicity and reliability. Two geometries of novel conical thermal receivers were designed, constructed …